In surgical operations of the chest or abdomen, it is often necessary to use a retraction apparatus to retain tissue away from the operative site. Referring to FIG. 1, a retraction apparatus includes a housing member 30 configured to lock onto a circumferential ring 16 located above the operative site 20. To maintain the ring 16 in a fixed position, the ring is connected to a support post 10 adjacent to the operation site 20. An extension arm 14 is attached to the support post 10 for supporting the circumferential retention ring 16. A retraction blade 18 is placed within the housing member 30 and is used for grabbing the tissue around the surgical incision. The housing member 30 also includes a ratcheting mechanism and/or a tilting mechanism to draw the retraction blade 18 away from the incision, thereby effecting the pulling away and/or lifting of the tissue around the incision to expose the desired surgical area. Examples of such retractor systems are disclosed in U.S. Pat. No. 6,620,097, the contents of which are expressly incorporated herein by reference. These prior art retractor systems enable the tilt and the movement of the retractor blade in and out of the wound site. They can also provide angular adjustment, or rotation, of the retractor blade without having to remove the ratchet from the ring.
In some cases it is desirable to mount the three-dimensional tilt ratchet (3D-ratchet) on various type of support structures or to move the 3D-ratchet to different positions around the support structure. Accordingly it is desirable to have an easy mechanism for mounting and dismounting the multi-position tilt ratchet onto various types of support structures. It is also desirable to be able to lock the 3D-ratchet onto the support structure and still allow for positional changes around the support structure while the ratchet remains locked.